(1)原式=(2a-2b+a-2b)/(a-2b)(a-b)*(a-2b)/(3a-4b)(a+b)
=(3a-4b)/(a-b)*1/(3a-4b)(a+b)
=1/(a²-b²)
(2)原式=(a+b)(a-b)/(c-b)(a-c)(a-b)-(b+c)(c-b)/(a-b)(a-c)(c-b)-
(a+c)(a-c)/(a-b)(c-b)(a-c)
=(a²-b²-c²+b²-a²+c²)/(c-b)(a-c)(a-b)
=0
(1)原式=(2a-2b+a-2b)/(a-2b)(a-b)*(a-2b)/(3a-4b)(a+b)
=(3a-4b)/(a-b)*1/(3a-4b)(a+b)
=1/(a²-b²)
(2)原式=(a+b)(a-b)/(c-b)(a-c)(a-b)-(b+c)(c-b)/(a-b)(a-c)(c-b)-
(a+c)(a-c)/(a-b)(c-b)(a-c)
=(a²-b²-c²+b²-a²+c²)/(c-b)(a-c)(a-b)
=0